Objectives: To demonstrate the pharmacokinetic equivalence of CT-P13 and its innovator infliximab (IFX) in Japanese patients with rheumatoid arthritis (RA), and to compare the efficacy and safety of these drugs, administered for 54 weeks.
Methods: In a randomized, double-blind, parallel-group, multicenter study, 3 mg/kg of CT-P13 or IFX, in combination with methotrexate (MTX) (6-16 mg/week), was administered for 54 weeks to Japanese active RA patients with an inadequate response to MTX, to demonstrate the pharmacokinetic equivalence, based on the area under the curve (AUC(τ)) (weeks 6-14) and C(max) (week 6) of these drugs, and to compare their efficacy and safety.
Results: The CT-P13-to-IFX ratios (90% confidence intervals) of the geometric mean AUC(τ) and C(max) values in patients negative for antibodies to infliximab at week 14 were 111.62% (100.24-124.29%) and 104.09% (92.12-117.61%), respectively, demonstrating the pharmacokinetic equivalence of these drugs. In the full analysis set, CT-P13 and IFX showed comparable therapeutic effectiveness, as measured by the American College of Rheumatology, Disease Activity Score in 28 joints, the European League Against Rheumatism, and other efficacy criteria, at weeks 14 and 30. The incidence of adverse events was similar for these drugs.
Conclusion: CT-P13 and IFX, administered at a dose of 3 mg/kg in combination with MTX to active RA patients, were pharmacokinetically equivalent and comparable in efficacy and safety.
Keywords: Biosimilar; CT-P13; Infliximab; PK equivalence; Rheumatoid arthritis.